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Johnson engine

Classifieds · 9 of 9 known posts recovered

DavidJ · Apr 17, 2004 06:21 PM

#0 source

I need a 32 Johnson 6 bolt cylinder head, and a 29 backplate to fit this case. Thanks to anyone who can help.

Gary Tultz · Apr 17, 2004 10:54 PM

#1 source

I have a small case Johnson backplate you can have. No charge . Email your address.

Gary T

DavidJ · Apr 18, 2004 03:43 PM

#2 source

Thanks a bunch, Gary! You are what makes this hobby so much fun. Hopefully someone will have a 32 cylinder head so I can get this engine in the air.

DavidJ · Apr 25, 2004 10:56 AM

#3 source

Gary, your Johnson backplate arrived, and I'm dancing on the clouds!
Thank you very much. I'm still hoping someone will have mercy on me and sell me a Johnson 32 6 bolt cylinder head.
Has anyone had any experience with chucking a .35 head in a lathe and
turning it down to the .32 size? It's probably a dumb idea, but I can still wonder.

De Hill · Apr 28, 2004 11:23 AM

#4 source

Ecxactly what part of the Johnson head are you thinking of turning down?

De Hill

DavidJ · Apr 28, 2004 12:07 PM

#5 source

De, I'm sending you an email so I won't embarrass myself any further
here, since I've just made a startling discovery.

Cary · Apr 28, 2004 02:30 PM

#6 source

Now you have us curious!!!?

Cary

shholt · Apr 28, 2004 04:08 PM

#7 source

Unless I'm badly mistaken, the Johnson .32 was a .35 top end on a .29 bottom end. If this is really the case, the .35 head is already the correct diameter for the .32.
Steve
The older I get, the better I used to fly!

DavidJ · Apr 28, 2004 04:29 PM

#8 source

LAST EDITED ON Apr-28-04 AT 04:29 PM (CDT)

According to Johnson Operating Instruction Specifications a .29
has a bore of .718 and my .29 piston measures exactly that: .718;
and specs say a .32 has a bore of .750 and my .32 (engine A) piston measures exactly that: .750
The .32 for which I have been advertising to find a head (engine B) has a bore of .724 - the piston measures .724 and fits snugly into the cylinder which came with the engine.
Engine A's .32 head will not fit on on Engine B's .32 cylinder.

Has anyone else had this experience?

De Hill has suggested I find a .35 head and have it turned down to
.724 so the combustion chamber will fit in this cylinder. I guess it
wasn't such a dumb idea after all.